A 0.06 mm2 6 dBm IB1db wideband CMOS class-AB LNTA for SAW-less applications

A wideband low-noise transconductance amplifier (LNTA) with high linearity is proposed. The differential LNTA adopts complementary common-gate, current mirror and common-source (CG-CM-CS) scheme to achieve noise and distortion cancellation and g_m-enhancement. The gain expansion of the class-AB CS stage compensates the gain compression of the CG-CM stage, which leads to a high large-signal linearity. A wide input matching bandwidth is achieved by utilizing a pi-type input matching network without the use of on-chip bulky inductors. Designed in a 0.18μm CMOS process, the simulation results show that it provides a minimum NF of 3 dB, and a maximum transconductance of 78.1 mS from 0.1 to 3.6 GHz. An input 1-dB compression/desensitization point and an IIP3 of 8.23/6 dBm and 17.3 dBm, respectively, are obtained. The NF is degraded by 0.3 dB with a 0 dBm blocker. The circuit draws 10.4 mA from a 2.5 V supply and the core area is only 0.5 × 0.12 mm².